This invention relates, in general, to a computer provided with a power forced shutdown function, more particularly to a computer provided with a power forced shutdown function for shutting down the power thereof forcibly.
Notebook model computers provided with a display and a keyboard respectively are excellent in portability. Such a computer detects whether or not a key is pressed through scanning of its key matrix including a plurality of predetermined keys provided on the keyboard.
Computers in recent years can use an OS or an application program to turn on or turn off their powers. For example, when such a notebook model computer is not used, the computer is usually set in a so-called energy-saving mode for minimizing the battery power consumption or shutting down its power supply. The OS or application program shifts the computer mode into the energy-saving mode automatically or in response to an instruction from the user.
Such a computer is also provided with a power switch respectively and the power switch is turned on/off to supply/shut down the power thereof. Many of those power switches are not used to supply and shut down the battery power and the AC power directly, thereby the OS or the application program can be used to manage the power to the computer as above described. More concretely, the computer is provided with a power circuit for supplying or shutting down the battery power and the AC power thereof, so that the power switch outputs a signal for directing power-on and power-off to this power circuit.
Consequently, a computer, when shutting down the power, detects a signal for directing power-off from the power switch or from the OS or the application program so as to control the power.
However, when the computer shuts down the power with an instruction from the user, a plurality of keyboard operations and a special hardware configuration have been required as predetermined in order to avoid erroneous operations.
In order to avoid such a problem, there is disclosed a technique for shutting down the power of a notebook model computer forcibly in any status (c.f. Published Unexamined Patent Application No. 10-307650). According to this technique, a key code for emulating a predetermined keyboard operation is output to the main CPU as a DATA signal, thereby shutting down the power. Because such a keyboard operation is output to the main CPU as a signal with use of an existing keyboard controller that emulates the keyboard operation, thereby controlling the power, the power is controlled without requiring any special hardware configuration.
However, in order to enable the power of a computer to be shut down by controlling the power with a signal output to the main CPU with use of an existing keyboard controller, the main CPU must be kept in the normal operation status. More concretely, one of the OS and application programs must run normally in the computer. Sometimes, however, the OS or the application program is hung up in the computer. In such a case, because it is difficult to shut down the power of the computer by controlling the power as above described, such a complicated work as removal of the AC power supply and the battery power supply is needed to shut down the power.
This is why many computers are provided with additional components including a reset switch, which can shut down the power forcibly even when any of the OS and application programs is not running normally. And, addition of such a reset switch makes the power unit complicated. Especially, in the case of a notebook model computer, which is pressed for simplification in structure and reduction in cost, it has been strongly demanded to reduce the number of components to be mounted therein.
Under the above circumstances, therefore, it is an object of the present invention to provide a computer having a power forced shutdown function, which can shut down the computer power in a simple structure and without depending on the status of the computer.
The computer of the present invention, provided with a keyboard and a keyboard controller for converting a signal generated through scanning of a key matrix including a plurality of predetermined keys in the power-on status to a key code and transferring the key code to a processor, has a power forced shutdown function. The present invention thus enables the power to be shut down easily in the object computer allowing a special key being excluded from the key matrix including a plurality of predetermined keys and being included in the keyboard.
In the first aspect of the present invention, in a computer having a keyboard and a keyboard controller, the keyboard controller transforming a signal generated through scanning of a key matrix, including a plurality of predetermined keys in a power-on status, to a key code and transferring the key code to a processor, there are included: a power switch shiftable between a normal position and a pointed position, the switch outputting a signal representing a turn-on or a turn-off of the computer in response to a shift of the power switch to the pointed position; a power circuit supplying or intercepting power voltage in response to the signal transferred from the power switch; and a special key being excluded from the key matrix and being included in the keyboard, the key outputting a signal representing a power forced shutdown by being depressed in conjunction with the shift of the power switch to the pointed position.
In the present invention, a keyboard means an input device built in such a computer as a notebook model one beforehand as a component of the computer body. It is a hardware unit used for part of the input function of the computer. This keyboard includes a plurality of keys disposed as predetermined, for example, so as to conform to the JIS-based key disposition, etc. Recently, the keyboard is often provided with special keys for certain functions and function keys to which the user can assign his/her desired functions.
In the above described first aspect, the computer is provided with a keyboard controller for converting a signal generated through scanning of a key matrix including a plurality of predetermined keys provided on the keyboard in the power-on status to a key code and transferring the key code to the processor. Which key of the keyboard is pressed can be judged by scanning the key matrix. The computer is also provided with a power switch shiftable between a normal position and a pointed position and used to output a signal representing power-on or power-off of the computer in response to the shift of the switch to a pointed position. The power circuit supplies or shuts down the power voltage in response to a signal from this power switch. The keyboard includes a special key which is not included in the key matrix. The special key, when pressed in accordance with the shift of the power switch to a pointed position, outputs a signal representing a power forced shutdown. Consequently, the signal representing the power forced shutdown can be output in response to a depression of the special key while the power switch is shifted to a pointed position. Consequently, the signal representing the power forced shutdown is entered to the power circuit directly even when none of the OS and application programs is running normally in the computer. The power voltage can thus be shut down forcibly. There is thus no need to add such a new hardware device as a reset switch to the configuration of the computer.
The power circuit is configured by a logic circuit for outputting a signal directing supply or shutdown of a power voltage in response to a signal from the power switch and a power driving circuit for generating the power voltage and for supplying or shutting down the power voltage in response to the instruction signal, and said signal representing said power forced shutdown is entered to said power driving circuit. More concretely, the power circuit needs such a unit as a keyboard controller for converting a signal generated through scanning of a key matrix to a key code and transferring the key code to a processor, but the unit requires no actual part for supplying and shutting down the power voltage. More concretely, such a part should preferably be separated from the power circuit. In such a case, the logic circuit is in charge of such processings as scanning of the key matrix, as well as outputting of a signal for directing turn-on or turn-off of the power voltage in response to a signal from the power switch. And, the power driving circuit is in charge of the function for generating a power voltage and supplying or shutting down the power voltage in response to a instruction signal. Consequently, the power driving circuit receives a signal representing a power forced shutdown directly even when the shift of the power switch is not detected while none of the OS and application programs is running normally in the computer. The power voltage can thus be shut down forcibly.
The special key should preferably be a function key to be grounded when it is pressed. Notebook model computers are often provided with keys used for certain functions, as well as function keys to which the user can assign functions respectively. Those function keys include some keys that can output a signal to the computer body regardless of scanning of the key matrix. For example, there is a switch key that takes a fixed potential (a ground voltage and a predetermined level power voltage) when it is pressed. This key can be used together with a conventional key without using any special new key.
The power switch can further output a signal representing the status of a special key when it is shifted to the normal position. Such special keys as the conventional function keys, when the computer is powered, are often assigned to certain functions and other functions assigned by the user. Consequently, those special keys should be used as normal keys when not directed for a power forced shutdown. This is why each of those special keys can be used as normal keys when shifted to a normal position if it further outputs a signal representing the status thereof, that is, whether or not it is pressed when the power switch is shifted to the normal position.
Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention.